The other bats collected today will be returned, ruffled but unharmed, to their hibernation perches, but this one will be euthanized for laboratory tests. Reluctantly, Slack and Mike Armstrong from the U.S. Fish and Wildlife Service do the deed with a vial of the chemical isoflourine. “Sorry, little girl,” Armstrong says. One bat sacrificed, in hopes of saving another million of its kind.

Barton has just spent eight days squeezing her lanky frame through unexplored sections of Lechuguilla Cave, a southern New Mexico cave thought to be the deepest in North America. Access is restricted to protect Lechuguilla’s delicate crystals and stalactites as well as its relatively undisturbed microbial community. Though Barton is an expert caver, more than a week in tight passages has tested even her stamina, leaving her knees sore and her gait stiff. But she saw a part of the world that’s never been seen before.

She grew up in Bristol, England, in a family she describes as “not the slightest bit outdoorsy.” When she was 14, she participated in a required high-school course that included rock-climbing, kayaking, horseback riding and a day of caving. “Everything terrified me but the caving,” she says. “In the cave, I stayed in the back of the group thinking, ‘I love this. This is cool.’”

Barton began to explore the caves near her hometown, caving with friends several times a week (“My mother would say, ‘You can’t go caving now! It’s dark!’” she says with a laugh). As her curiosity and enthusiasm grew, she began exploring more difficult and distant caves.

She had also been fascinated by microscopic organisms ever since hearing BBC-TV naturalist David Attenborough marvel about the complexity of life in a single drop of water. When she was 14, Barton swept her hair against a petri dish of nutrients in science class. “By the next day, all kinds of disgusting things had grown out of it,” she remembers with a grin. After studying biology at the University of the West of England, she moved to the University of Colorado to pursue a PhD in microbiology.

A collaborator, Norman Pace, suggested she study the microscopic life in caves, which scientists knew little about. “There aren’t many microbiologists who can go where you go,” Pace told her. Barton didn’t want caving—her hobby—to become her job, but eventually she relented and began to plumb caves in Mexico, Guatemala, Belize, Venezuela and throughout the United States for signs of microbial activity. Caves, she has found, are swarming with microbes adapted to life without photosynthesis. She has identified microbes that can digest industrial chemicals and others with antibiotic properties—organisms that she and other researchers are studying for their potential to treat drug-resistant human diseases.

Barton’s experience schooled her in the tenacity of these tiny life-forms. For her PhD research, she studied a bacterium that infects the lungs of cystic fibrosis patients, and she came to think of caves as somewhat like human bodies—complex places that host a vast variety of organisms, each adapted to its environment in a different way. Yet when Barton heard that a bat-killing fungus had managed to spread from caves in New York State all the way to West Virginia in just two years, even she was surprised by its velocity.

“if you sat down and thought, ‘What would I design to kill bats, and how would I design it?’ and you took time to think about the worst possible combination of factors that a pathogen would have, this would be it,” says Barton.

Because G. destructans thrives in cool temperatures, it attacks bats while they hibernate for the winter, when their immune systems are effectively shut down. The fungus may spread from bat to bat, and when the animal colonies disperse in the spring, the fungus may persist in cave sediment, poised to infect the next winter’s arrivals. Bats with white-nose syndrome rouse more frequently from their winter torpor, which causes them to waste precious body fat at the coldest time of the year. (In what’s been dubbed the “itch and scratch” hypothesis, some scientists posit that the bats are disturbed by the fungus, which accumulates on their muzzle and wings.) The fungus also infects the bats’ delicate wing membranes, eating away at the skin until the wings resemble torn, crumpled tissue paper.

The disease was discovered in early 2007, when bats in upstate New York started behaving oddly. Instead of hibernating through the winter, they flew into neighborhoods during the day, wandering dangerously far from their caves. “There would be three feet of snow and it would be 20 degrees—not bat-flying weather—and you’d see bats flying out and taking off into the distance,” says Al Hicks, then a wildlife biologist for the New York State Department of Environmental Conservation. “You’d know every darn one of them was going to die. It was awful.”

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